We take the total number of Advanced Placement, International Baccalaureate and Advanced International Certificate of Education tests given at a school each year and divide by the number of seniors who graduated in May or June. I call this formula the Challenge Index. With a few exceptions, public schools that achieved a ratio of at least 1.00, meaning they had as many tests in 2013 as they had graduates, were put on the national list at washingtonpost.com/highschoolchallenge…. I think 1.00 is a modest standard. A school can reach that level if only half of its students take one AP, IB or AICE test in their junior year and one in their senior year.

One reason, according to education columnist Jay Mathews who created the index, is that many schools limit access to advanced courses by requiring that students be recommended by a teacher or earn a certain grade point average to sign up.

Hey, I am all for eliminating barriers to advanced courses and to any other courses that might hold students back or push them to the side unfairly or unnecessarily. I know that happens. But I am even more about eliminating this index.

Since when is “challenging” defined solely by taking tests published by a few commercial organizations, even if they test courses that are well put together and rigorous? I can tell you about plenty of excellent high school courses that are challenging and that have nothing to do with AP, IB, or AICE. So can most high school teachers. And, this may be naïve, but I would like to believe that U.S. high schools can offer a challenging curriculum for all students, not just for those in special advanced courses. In fact, I believe that the existence of special advanced courses is sometimes used unwittingly by schools to excuse a lackluster curriculum for the rest of the students—that is, focus on the prestigious advanced courses and let the others fall where they may.

When I developed curricula for high schools in school districts around the country, I used to say to teachers, “Let’s write the best high school curriculum we can imagine—so good that we will not need AP courses. Our own courses in every grade need to be just as well thought out as AP courses. All of our students deserve a curriculum like that.”

So we would get together all of the resources we could find and do the research and hard thinking and debating that makes for great curricula. When we wrote the English and math curricula for the Early College high school I co-founded in New York City, our principal, Chris Aguirre, had the idea of bringing college professors into our curriculum planning summer sessions—to ensure that the curricula we wrote for our students would lead perfectly into college courses, like the ones our third-year students took on our college partner’s campus.

At our Early College high school, we were able to put into practice what our principal and I firmly believed: If students are smart enough and/or motivated enough, send them to college early so that they can take actual college courses for actual college credit. Make the high school curriculum good enough for all students so that it can be a strong foundation for college work—on the college campus, not in the high school. We sent students to college for two or three courses in their third year with us (usually introductory engineering and architecture courses), and we sent them to take college courses full time in their fourth year with us when they had already finished their high school requirements. How is that not a challenging high school? And yet, according to the Challenge Index, we would have gotten no credit for sending students to take college courses two years early. That kind of extraordinary story is true for Early College high schools all across the country.

While I am not particularly familiar with IB and AICE tests, I have seen AP courses and exams for decades (literally, since I took an AP English exam in high school in 1970). As I have worked in school districts across the country over many years, I have seen AP grow and grow. It has almost become synonymous with “rigorous curricula.” The College Board has done a great marketing job—to high schools and middle schools and school districts and school boards and parents and students. Oh, and to colleges, too, as admissions staff judge the high school records of freshman applicants.

I can continue to live in a world where AP courses exist. Even where high school students believe they can’t get into a top college without having taken them. Even where colleges look perhaps over-fondly on applicants that took them.

But I can’t live in a world where they are the sole definition (along with IB and AICE) of “challenging.” That makes no sense. Or did I miss something?